Talking cats and seeing trees

The novel I'm writing now is a science fiction environmental plea to save the natural world.  It's set on a planet called Vidar, and I wanted that planet to have an active sense of aliveness. 

One of my life forms on Vidar is sentient trees.  Gareth Powell has sentient forests in his Embers of War novels, but he doesn't go into the details of how those trees became self-aware.  I wanted to tackle the challenge of how they saw and communicated with the planet around them.

Everyone knows that trees can't talk and can't see, but I wanted them to be able to do both of those things to a high level.  I needed them to have those senses at a level where they could interact with my human colonists.  But I also didn't want to do something that isn't scientifically possible, with a big enough stretch of the imagination.

It's not strictly true that trees don't talk.  They just don't talk with mouths, or with a language spoken out loud.  But when they're attacked by insects they give off scent signals to other trees, warning of the attack.  And they are connected via mycorrhizal networks to other trees.  And the mycelium in those networks carry electrical signals.  

So the obvious thing to do was to turn this into a communication system that would work with humans too.  That required a bit of adjustment of both humans and trees.  I'd already made some of my humans telepaths, so they would be able to pick up broadcast signals.  So I could beef up the trees' mycorrhizal networks to broadcast much stronger signals, which the humans could detect.

That would get the life forms able to talk to each other.  But that wasn't the whole story.  This was a first contact situation, and humans have no Rosetta Stone to help them uncover the alien language of the trees.  They needed the help of someone who already knew the trees' language.

Often in science fiction we have to find a way round what in reality would be decades of mind-numbing work learning an alien language.  For the sake of the story, we need some kind of Universal Translator.  But in first contact situations even that wouldn't help.  Someone has to teach the Universal Translator the language in the first place.

So who did know the trees' language and could teach it to the humans?  Step forward those pesky bioengineered big cats again.  They were altered by humans a hundred years ago, then dumped on Vidar.  Left alone since they came here, they've reproduced and adapted - and learned to talk to the trees.

The cats were bioengineered to be early versions of Feliforms, intended to work in attack squads alongside human telepaths.  So the bioengineering the cats were subjected to made them telepaths.  And the colonists have telepaths among their numbers, who quickly establish a rapport with the cats.  The cats in turn help the humans speak to the trees.  Problem solved.

So far, so good.  But at the end of the book I need the trees to see.  How to do that?  Eventually I decided to put compound eyes on each leaf.  But then the trees needed some other mechanism when they'd dropped their leaves for the winter.  Light-sensitive strips in their trunks are used then.  So even when their leaves drop, the trees can still see, even if their vision is more restricted.

Now I've figured out how my world works, I need to decide how it can defend itself from hostile humans.  This is a big challenge, given that they're a small civilian colony and don't have access to armed troops.  So they're going to have to get the planet to help defend itself.  

There is another mysterious lifeform on Vidar which is in contact with the colonists' ring of communication satellites in orbit above the planet.  And that ring of satellites has evolved a high-level sentient AI, which comes in very handy when you need someone to look out for possible danger appearing from space.

But I still have the problem that my colonists don't have a convenient army to defend them.  They're an out of the way colony that has effectively been abandoned by the central administration.  And they've discovered that Earth's authorities aren't very keen on sending help to far-flung colonies when they ask for it.  So it's up to the colonists to use the resources around them and the limited amount of tech they brought with them to defend themselves and their unique planet.

That defence will involve the big cats, the trees, and the humans working together.  It will also involve the humans using some hastily-printed defences.  And, most importantly, lots and lots of ingenuity.   Oh, and they'll need some big water hoses too.

I'm really looking forward to writing the scenes of the defence of Vidar.